In the production of individual sheets from webs, particularly in the manufacture of individual preprinted business forms, it is desirable to produce large webs at one stage, and then to subsequently break up the webs into individual forms. However, in some circumstances it is highly desirable to integrate the forms produced side by side in a larger web in the final array of business forms produced. The present invention provides a method and apparatus for cost effectively accomplishing that function.
The method and apparatus according to the present invention use two or more cutters that act on individual web sections after they are slit from a main web at least two individual sheets (typically business forms) wide. The cutters are synchronized in a particular manner, the web sections are fed to the cutters, and the individual sheets removed from the cutters in such a manner so that an array of sheets (typically business forms) is produced with alternating sheets in the array from alternating web sections. Such a construction provides high reliability while obtaining high speed operation in an on-line environment. Also such a system reduces the complexity of the equipment downstream from the cutters, is simple and easy to use and construct, and has a relatively small "footprint" so that floor space taken up is relatively small. While the invention is particularly suitable for producing an in seriatim array of sheets, with a spacing between the sheets (which spacing may be adjustable by controlling the speed of operation of components downstream of the cutters) practice of the method and operation of the apparatus may be modified to also produce shingled sheets, or sheets stacked one on top of the other.
According to one aspect of the present invention a method of producing an array of sheets from a web is provided comprising the following steps: (a) Moving a web, at least two sheets wide, in a first direction. (b) While practicing step (a), slitting the web to produce at least two web sections. (c) Redirecting the two web sections from step (b) so that they move in different paths. (d) Cutting the two web sections into individual sheets. And (e) redirecting and combining the individual sheets into a single array of sheets with alternating sheets in the array from alternating web sections.
Step (c) is typically practiced by redirecting the two web sections so that they are substantially vertically aligned with each other prior to the practice of step (d). Step (d) is preferably practiced using different cutters for the different web sections that are synchronized and out of phase with each other. When only two web sections are involved (rather than more) the cutters are substantially 180.degree. out of phase with each other.
Steps (a) through (d) are typically practiced while the web or web sections are moving at a first linear speed, and step (e) is also practiced at the speed of the sheet substantially immediately after cutting so that they move at a second linear speed, at least about twice as great as the first speed (where two web sections are provide) at least three times great for three web sections, etc. While other modifications are possible (such as shown per se in U.S. Pat. No. 4,696,464), steps (a) through (e) are typically practiced to produce an in seriatim array of sheets with a spacing between the sheets determined by the increase in speed provided during the practice of step (e). Step (c) is preferably practiced to move the web sections in first and second different substantially vertical loops, the first loop having a greater length than the second loop so that the web section in the first loop leads the web section in the second loop by the length of an individual sheet formed in the practice of step (d) divided by two.
In the preferred manner of operation, the web used in step (a) comprises a web of pre-printed paper business forms, and the individual sheets in the array of step (e) are individual pre-printed paper business forms.
According to another aspect of the present invention the apparatus for producing an array of individual sheets from a web is provided. The apparatus comprises the following components: Means for moving a web at least two sheets wide in a first direction. Means for slitting the web while moving in the first direction to produce at least two web sections. Means for redirecting the two web sections so that they move in different paths, Means for cutting the two web sections into individual sheets. And means for redirecting and combining the individual sheets into a single array of sheets with alternating sheets in the array from alternating web sections.
The means for cutting the two (or more) web sections into individual sheets may comprise any conventional structure that allows synchronized cutting of the web sections into sheets. While any conventional construction may be used, in the preferred embodiment of the invention the means comprise first and second sets (or more sets if more than two web sections are slit from the original web) of cutting and anvil cylinders. Preferably the cutting cylinders each have a cutting blade, and where two web sections are provided the cutting blades of the cutting cylinders are substantially 180.degree. out of phase. The cutting and anvil cylinders of the various sets are preferably either synchronized electrically, or mechanically driven together so as to maintain the appropriate phase relationship between the cutting blades. Of course, the cylinders can be larger so that two or more cutting blades are provided for each cylinder, in which case each of the corresponding sets of cutting blades from each of the cutting cylinders are substantially 180.degree. out of phase.
The means for slitting the web while moving in the first direction may comprise any conventional slitting mechanism including (but not limited to) rotating wheel cutters, reciprocating blades, scissors cutters, etc.
The means for redirecting two web sections so that they move in different paths may also comprise any conventional components which can accomplish that general function, including rollers, movable carriages, stationary guides whether angled, straight line, or curved, or the like. In the preferred embodiment the means for redirecting the two web sections so that they move in different paths comprise means for redirecting the two web sections so that they are substantially vertically aligned with each other prior to contacting the cutting means. For example, the means for redirecting the two web sections may comprise a first set of first and second curved surface elements (which may be rollers, but preferably comprise stationary curved surface elements) that are vertically spaced from each other, and disposed at different angles to the horizontal. Also, a second set of first and second curved surface elements (rollers or stationary elements) may be provided that are vertically and horizontally spaced from each other and closer to the cutting means than the curved surface elements.
The means for redirecting and combining the individual sheets into a single array of sheets may also comprise any conventional structure that accomplishes that purpose including merger/singulator modules, complex conveyor systems such as shown in U.S. Pat. No. 4,696,464, or the like. However, for simplicity and reliability the means for redirecting and combining the individual sheets preferably comprises first and second sets of gripper rollers for gripping sheets while being cut by the cutting means, and first and second singulating conveyor belt assemblies cooperating with the first and second sets of gripper rollers, respectively. The first and second singulating conveyor belt assemblies may include top and bottom belt sections, and a central converging belt section between the top and bottom belt sections. The central converging belt section may comprise a first belt subsection cooperating with the top belt section, and a second belt subsection cooperating with the bottom belt section, and a common roller of the first and second belt subsections between the top and bottom belt sections. The belts used with the common roller may comprise spaced individual conveyor belts or tapes.
The means for moving the web that is at least two sheets wide in the first direction may comprise any suitable conveying apparatus. Some examples of conventional apparatus that may be used for that purpose include sets of drive rollers, with or without idler rollers or redirecting rollers, pin feed tractors, pressure feed tractors, air blast drives, etc., powered by any suitable source of power including electric motors, hydraulic motors, fluidic motors or the like.
While the apparatus is typically operated so that means for redirecting and combining the individual sheets produces an in seriatim array of sheets, with spacing between the sheets determined by the increase in speed provided by the means for redirecting and combining the individual sheets compared to the speed of the means for moving the web in the first direction, the apparatus may also be operated to provide an individual sheet stacked one on top of the other, or shingled with any degree of displacement in the shingling operation.
The increase in speed provided by the means for redirecting and combining individual sheets may be accomplished by utilizing mechanically tied together components having particular (and perhaps adjustable otherwise variable) gear ratios or pulley ratios, or by utilizing conventional computer controls which synchronize operation of various motors and provide for a speed differential operation thereof.
It is a primary object of the present invention to effectively and relatively simply and reliably produce an array of sheets from a web at least two sheets wide. This and other objects of the invention will become clear from an inspection of the detailed description of the invention and from the appended claims.